Auxetic materials have a negative Poisson's ratio, that is, they expand laterally when stretched longitudinally. Negative Poisson's ratio is an unusual property that affects many of the mechanical properties of the material, such as indentation resistance, compression, tension and shear stiffness, and certain aspects of the dynamic performance. Auxetic foam was fabricated from a conventional polymeric foam. The unusual mechanical properties of auxetic foams are attributed to the deformation characteristics of re-entrant microstructures. There are four main aspects to the project. Firstly, the fabrication method for auxetic foams has been examined and developed further. Secondly, the microstructure of the foams has been characterised using electron and optical microscopy. Thirdly, the foams have been tested for their static and dynamic mechanical properties. Comparative tests have also been performed on conventional, non-auxetic foams. Fourthly, theoretical models have been developed to relate the observed microstructures to their properties.